Liquid cleansing products are extensively used as hand cleaners, shampoos, and for many other purposes. The current invention is concerned primarily with cleansers used for cleaning skin but is not limited to that application. The cleansers of interest are aqueous based and contain surfactant.
In order to achieve controlled use of a liquid cleansing product, it is desirable to have a viscous but pourable or pumpable product. A thin, watery product is too easily spilled and wasted when used and does not have good consumer acceptance. Guar gum and its chemically modified derivatives are well known product ingredients used in a wide variety of aqueous based products and are described variously as thickeners, gelling agents, suspending agents, protective colloids, binder materials, agglomerating agents, etc. As used herein, the term "guar material" is used to denote guar gum or derivatives produced by chemically modifying guar gum unless specifically noted otherwise.
In the present invention, guar materials have been found to be effective as thickening agents in liquid cleanser formulations. In addition, it has been found that guar material, and particularly certain derivatives of guar gum, imparts a desirable smooth, slippery skin feel to the liquid cleansing products. However, cleansing products formulated with the levels of guar material needed to provide the desired thickening and skin feel properties are not stable, but tend to separate. A thick paste, presumably high in guar material content, settles to the bottom of the product container. The addition of carboxyvinyl polymer to such cleansing product formulations has been found to substantially reduce or completely eliminate such separation.
Carboxyvinyl polymers are a family of acrylic acid copolymers marketed by the B. F. Goodrich Company, New York, N.Y. under the tradename of Carbopol. Carboxyvinyl polymers are well known ingredients that impart many of the same functional benefits as guar materials to aqueous based compositions. In fact, carboxyvinyl polymers and guar materials are often indicated as being interchangeable ingredients in particular formulations. For example, in U.S. Pat. No. 3,697,644 issued to Laiderman on Oct. 10, 1972, carboxypolymethylene (a carboxyvinyl polymer, Carbapol 934) and guar gum (a guar material, Jaguar A-20-D from Stein, Hall and Company) are specified as alternative thickening agents which act as a protective colloid to hold a dispersed phase in suspension in cosmetic compositions. In U.S. Pat. No. 3,939,260 issued Feb. 17, 1976, to Lafon, Carbopol and guar gum are used alternatively as a thickener or binder in therapeutic and cosmetic compositions.
In U.S. Pat. No. 3,591,680 issued to Green et al. on July 6, 1971, the use of Carbopol or guar gum as a suspending agent in antacid compositions is disclosed. Guar gum or Carbopol can be used as a binder material in producing a battery gel substance in U.S. Pat. No. 3,880,672 issued to Megahead et al. on Apr. 29, 1975. Green and Megahead consider guar gum and carboxyvinyl polymer to be different materials that can be used interchangeably for the same purpose along with a number of other materials. These references regard the individual materials or any combination of them to be the same. Neither reference specifically discloses a combination of carboxyvinyl polymer and guar gum, and neither suggests that such a combination might have more desirable properties than either used separately in a liquid skin cleanser.
It is therefore an object of the present invention to provide liquid cleansing compositions which deliver good skin feel and are stable.
It is a further object of the present invention to provide liquid cleansing compositions which utilize particular levels of a guar material and a carboxyvinyl polymer.
These and other objects will become apparent from the following detailed description. All percentages herein are by weight unless otherwise specified.